WASHINGTON (Reuters) - NASA scientists have identified the
smallest black hole ever found -- less than four times the mass
of our sun and about the size of a large city.

But the mini-black hole, dubbed J1650, could still stretch
a person into a "strand of spaghetti" with its pull, the
researchers told a meeting in Los Angeles.

"This black hole is really pushing the limits. For many
years astronomers have wanted to know the smallest possible
size of a black hole, and this little guy is a big step toward
answering that question," Nikolai Shaposhnikov of NASA's
Goddard Space Flight Center in Greenbelt, Maryland, said in a
statement.

It would likely be stronger than bigger black holes found
at the centers of galaxies. Shaposhnikov said if someone
ventured too close to J1650, its gravity would "stretch your
body into a strand of spaghetti."

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Like other black holes, it was formed by a star that ran
out of fuel and shut down, collapsing due to its own gravity.

Shaposhnikov and his Goddard colleague Lev Titarchuk used
NASA's Rossi X-ray Timing Explorer satellite and a new method
to estimate the size of the black hole, found in a system in
the southern constellation Ara, in our own Milky Way Galaxy.

It measures the oscillation of hot gas piling up near the
black hole as it sucks in matter, they told a meeting in Los
Angeles of the American Astronomical Society High-Energy
Astrophysics Division.

The new black hole has a mass of 3.8 Suns and would be
about 15 miles across, they estimate. "This makes the black
hole one of the smallest objects ever discovered outside our
solar system," Shaposhnikov said.

The smallest black hole previously identified was GRO
1655-40, with a mass of about 6.3 Suns.

"Amazingly, equations from Albert Einstein predict that a
black hole with 3.8 times the mass of our Sun would be only 15
miles across -- the size of a city," NASA said in a statement.

A collapsing star that was much smaller than J1650 would
likely form a neutron star and not a black hole, the
researchers said.